Ester oligomers

In a polyurethane elastomer analysed by isobutane CI-MS and CI-MS/MS in TD/Py-CIMS (TD, 20-200°C Py, 200-300 °C) mode MDI (diisocyanate), BDO (chain extender), Stabaxol P (stabiliser), AA/ BDO/HDO (cyclic adipate) and residual cyclic ester oligomers were identified [65]. 

Brunelle, D. J. and Serth-Guzzo, J. Titanate-catalyzed ring-opening polymerization of cyclic phthalate ester oligomers, Polym. Prep., 40(1), 566 (1999). 

Cured ethynyl-terminated ester oligomers prepared from the reaction of hydroxy-termi nated ester oligomers with 4-ethynyl benzoyl chloride exhibited higher Tgs and better solvent resistance than comparable unendcapped polymers (50). Biphenylene end-caps have been placed on imide (40, 51), quinoline (52, 53) and quinoxaline (53) oligomers. High temperatures (> 316°C"J are required to cure... 

Xu, R., Leonard J., and Bui, V.T. Vapor pressure for mixtures of methylene ester oligomers with /rdioxane and chloroform, /. 

Production of cyclic ester oligomers from linear polyesters 133... 

Brugel EG. Production of cyclic ester oligomers from linear polyesters by reactive extraction. WO 0268496, E.I. Du Pont de Nemours and Co., 2002. 

Pioneering work on phosphorus ester oligomers has been done by Monsanto in the U.S. (1), by Hoechst in Germany (2), and in the Soviet Union. These "itudies involved synthesis and flame retardant applications. The polycondensation of 2-chloroethyl phosphates as a route to oligomeric phosphorus esters (Equation 1) was first reported by Korshak al. (3). This Russian publication describes the polycondensation of tris(2-chloroethyl) phosphate at 240-280° under non-catalytic conditions. 

Kuhlman [5] re-polymerized macrocyclic ester oligomers in the presence of di-n-butyl tin oxalate, which had up to a 2 minute latency period and was followed by a rapid polymerization similar to that of di-n-butyltin glycolate. 

Polyethylene terephthalate (PET). At temperatnres above 300°C PET pyrolysis proceeds via a random-chain scission of the ester links to yield a mixture of terephthalic acid monomer and vinyl ester oligomers [47], The presence in the monomer of oxygen and a benzene ring imphes that the decomposition prodncts contain aromatic and oxygenated carbon componnds, like CO2, ketones and aldehydes [27],... 

Urethane-Based Hybrid Foams. Hydroxyl-terminated ester oligomers or vinyl esters which have terminal vinyl groups and pendant hydroxyl groups can react simultaneously with isocyanate groups and vinyl monomers in the presence of catalysts to obtain crosslinked hybrid polymers. 

All-trans unsaturated ester oligomers have been synthesized by lipase-catalyzed polymerization of diesters of fumaric acid and 1,4-butanediol.217 No isomerization of the double bond was observed, as opposed to the extensive isomerization found during chemical polycondensations. Crystallinity was found in the enzymatically formed unsaturated oligoesters prepared in acetonitrile, whereas industrial unsaturated polyesters are amorphous. 

As a result. In the anionic polymerization of lactones, low pol3rmer yield, uncontrollable molecular weight, broad distribution, coupling linkage, and cyclic ester oligomers contamination have been frequently encountered O In this paper, a new Improved process was revealed to eliminate such trensesterlflcatlons has been developed. Block copolymers with styrene and butadiene have been prepared and characterized by different techniques. 

Okumara, S., Iwai, M., and Tominaga, Y. (1984) Synthesis of ester oligomer by Aspergillus niger lipase. Agric. Biol. Chem., 48 (11), 2805-2808. 

This polymer generates hexafluoroalcohol on aeid-eatalyzed thermolysis and tends to have low eontrast. Addition of tert-hutyl ester oligomer into the formulation as a dissolution inhibitor helps to improve the development eontrast of the resist this partieular version, marketed by Clariant Corporaton, was the first commereially available resist designed for 157-nm lithography... 

As coimterparts to the imine containing intermediates, various ester oligomers from 1,4-butanediol and succinic acid were produced, having acid end groups. This means that succinic acid is used in excess in comparison to 1,4-butanediol. These oligomers are condensed with the imine containing intermediates. A typical structure is shown in Figure 9.2. 

Dicyanate resins are versatile thermosets and have been used in a wide variety of applications. For example, RTX-366 (Hunstman Chemical) is a high molecular weight cyanate ester oligomer with excellent dielectric properties (low... 

Sdf Assembly Measurements in Solution The critical micelle concentration (CMC) is the characteristic solution concentration at wiiich solubilized single molecules aggregate into micellar structures. A number of parameters, including osmotic pressure, conductivity, turbidity and surfiice tension e q>erience dramatic changes at the CMC. One method of determining the CMC involves surfiice tension measurements using a Wilhelnty plate. The CMC of various F-terminated cellulose ester oligomers and of xylans were determined in THF and water, reflectively. 

Mono-functional, F-terminated cellulose ester oligomers in THF were found to self-assemble into micellar structures at concentrations of between 10 to 10 moles L. The CMC depended on both the chemical nature of the oligomer (i.e., type of F-containing end group) and the size of the CTP-segment. 

Ester Oligomer Method Polyamic acid Method... 

Dicarboxylic esters and dicarboxylic ester oligomers (if glycol is used, OH-bearing polyols)... 

Lys-Met ethyl ester oligomer synthesis short peptide synthesis in trozen aqueous medium [29]... 

Figure 3.3 is a product ion scan for the MH 429 component. Product ions include the protonated -BDO-AA- m/z 201) and -HDO-AA- (m/z 119) units. The residual cyclic ester oligomers observed via CI-MS (Figure 3.1) may be identified as follows ... 

In summary, the competitive thermoplastic PU was found to be composed of MDI, BDO chain extender, and a mixed AA/BDO/HDO polyester. The only volatile chemicals found were the stabiliser Stabaxol P and some residual cyclic ester oligomers. 

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